I have a large open floorplan basement (6000+ cuft / 170 m^3) but don't plan to listen anywhere near reference (-20 or -15). Maybe 70% HT / 30% music. I can get 2 boxes of any size, so I was looking at Full Martys (11 cuft ported tuned to 16 Hz).
I'm trying to understand out the tradeoffs between various drivers (UM18-22, SAF184.03) in a full Marty.
From looking at some performance comparisons (e.g. gsg's table on their website, though perhaps I could learn how to use WinISD), it seems at these sizes the enclosure and port largely determine the low frequency extension and volume (for HT). So while the focus is on HT, it seems like I wouldn't gain that much ULE by going with say a Dayton UM18-22 vs B&C TBW-100 or lavoce 18" (SAF184.03): seems 2-3 dB at ~20 Hz but similar extension down to 14 Hz.
I would gain a lot in mid bass volume (though I don't listen very loud) but also quality? I've seen talk about the bass quality of these pro drivers, perhaps related to distortion and the lack of heat due to their efficiencies. Or is it not worth losing the Xmax, especially for an enclosure of this size? I will be using MiniDSPs and REW. Being able to use a weaker amp is also a bit enticing.
Any links for trying to understand this is also welcome.
I'm trying to understand out the tradeoffs between various drivers (UM18-22, SAF184.03) in a full Marty.
From looking at some performance comparisons (e.g. gsg's table on their website, though perhaps I could learn how to use WinISD), it seems at these sizes the enclosure and port largely determine the low frequency extension and volume (for HT). So while the focus is on HT, it seems like I wouldn't gain that much ULE by going with say a Dayton UM18-22 vs B&C TBW-100 or lavoce 18" (SAF184.03): seems 2-3 dB at ~20 Hz but similar extension down to 14 Hz.
I would gain a lot in mid bass volume (though I don't listen very loud) but also quality? I've seen talk about the bass quality of these pro drivers, perhaps related to distortion and the lack of heat due to their efficiencies. Or is it not worth losing the Xmax, especially for an enclosure of this size? I will be using MiniDSPs and REW. Being able to use a weaker amp is also a bit enticing.
Any links for trying to understand this is also welcome.
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That is like a room of 100 m2 .... nice 🙂
Firstly I would go for a tuning around 25 Hz. With some 18" you can always eq it a bit if necessary.
Secondly, I would rather go for more "smaller" than one or 2 large ones. Placed differently in the room will lower the influence of room modes and will result in much cleaner freq response and sound.
Most of the Pro woofers will need additional eq as they are not designed to work optimally down to 25 Hz.
But with this amount of space I think there are plenty of options.
Just one B&C TBW-100, in 150 l ported to 30 Hz, with 1300W will give 116 db at 25Hz .... that's insane
😀
But then again, more subs is the only way to battle room nodes (but will be a little less pronounced in a big room though).
Firstly I would go for a tuning around 25 Hz. With some 18" you can always eq it a bit if necessary.
Secondly, I would rather go for more "smaller" than one or 2 large ones. Placed differently in the room will lower the influence of room modes and will result in much cleaner freq response and sound.
Most of the Pro woofers will need additional eq as they are not designed to work optimally down to 25 Hz.
But with this amount of space I think there are plenty of options.
Just one B&C TBW-100, in 150 l ported to 30 Hz, with 1300W will give 116 db at 25Hz .... that's insane
😀But then again, more subs is the only way to battle room nodes (but will be a little less pronounced in a big room though).
I would go for the most Bl and least Qts possible. The B&C 18DS115 is a better driver then the 18TBW100. 18IPAL is even better then the 18DS115, but is expensive and does demand a powerful amp capable of driving not only the nominal 2 ohm load, but a very reactive load at that.
T-S Parameters in the 21st Century - YouTube
Bennett Prescott does a great job of explaining why you want as much Bl as possible.
The spl response will be all over the board in a normal room anyway, so DSP is a given if you want good bass quality. And if you have DSP then you don´t have to care much about the simulated response anyway.
T-S Parameters in the 21st Century - YouTube
Bennett Prescott does a great job of explaining why you want as much Bl as possible.
The spl response will be all over the board in a normal room anyway, so DSP is a given if you want good bass quality. And if you have DSP then you don´t have to care much about the simulated response anyway.
Cool video ... also just saw the on about power handling:
Power Handling Deep Dive - YouTube
Very informative 😉
Power Handling Deep Dive - YouTube
Very informative 😉
I have built subs with both the UM-18 and the TBW100. UM-18 in a smallish sealed box, TBW in a vented PA cabinet.
From modeling in WinISD, UM-18 would be better for a large low-tuned HT cabinet vs the TBW100. It has almost 2X the Xmax. That matters not much at all above 40hz, but very much below 20hz. You really can't EQ boost below the tuning frequency without blowing up the driver, in fact you should be high-passing to protect the driver below the system resonance.
Looking at higher and higher spec'ed pro drivers to get better LFE is barking up the wrong tree. They may outperform at 80hz with 4K watts but be no better at 20hz because the limiting factor down there is the Xmax.
From modeling in WinISD, UM-18 would be better for a large low-tuned HT cabinet vs the TBW100. It has almost 2X the Xmax. That matters not much at all above 40hz, but very much below 20hz. You really can't EQ boost below the tuning frequency without blowing up the driver, in fact you should be high-passing to protect the driver below the system resonance.
Looking at higher and higher spec'ed pro drivers to get better LFE is barking up the wrong tree. They may outperform at 80hz with 4K watts but be no better at 20hz because the limiting factor down there is the Xmax.
If you are looking for real lows and you have space enough, I would definitely go wild and make it BIG.
What other hardware do you have? Meaning, where are you gonna cross it?
What other hardware do you have? Meaning, where are you gonna cross it?
Why 25 Hz instead of the ~16 Hz I had mentioned? Seems like since my focus is on HT, I should try to get as much help at ultra low end as possible.
Unfortunately I can't swing more than 2 in this space, or rather I have 2 designated spots. But hey, originally I was only supposed to get 1 box, so moving to 2 should help a lot, right?
I could put 2 in each of the 2 spots, but I assume I won't get much benefit if they are nearly next to each other? Or will moving a foot be helpful in itself?
And how does that compare to a enclosure with two drivers?
I will be using a MiniDSP HD and am pretty comfortable with REW so this shouldn't be a problem. But since they aren't designed to work optimally down to 25, 20, or even 16 Hz, is it a mistake to get one over a HT woofer like the UM18-22?
Yeah, I don't even plan to listen to peaks anywhere near that either.But with this amount of space I think there are plenty of options.
Just one B&C TBW-100, in 150 l ported to 30 Hz, with 1300W will give 116 db at 25Hz .... that's insane
That's good to hear. Also, it's not a square, more like a U or J shape (utility closet in the center).
Thanks for the links, looks like I can learn a lot from Prescott.
Those drivers are a bit out of my price range, but those parameters do help me compare the UM18-22, TBW100, and SAF184.03. This order seems to go from worst to best in Bl and Qts, though in reverse order for Xmax. Does Prescott talk about Xmax at all? Seems like it's a more LFE specific parameter though.
Yes, that's what I've gathered, so I'm more just looking at distortion and SPL. But since I plan to listen to -20 below reference, so bass peaks of 95 dB, maybe just distortion?
I am curious about learning WinISD to look at the simulated response though to see exactly how much at the low end (14-20 Hz) I would be missing. gsg says 3 dB, which is still above my target peaks, which is why I was leaning towards those pro drivers if they have less distortion and better "quality".
What specific metrics should I be look at for quality (excluding frequency response, since I will be using MiniDSP)? THD, Group delay, transient response, waterfall plots, resonances? And which of those are much more dependent on the room and installing something like bass traps?
I'm new to WinISD, do you have any project files to get me started that I can play with?
The planned tuning is 16 Hz, so yeah I won't be boosting anything below that range (and will have a protective high pass). So the area of interest is around that 14~16-25 Hz range: how will I lose much with a lower Xmax driver? And since I have a large room, I don't expect to gain much with room gain.
My target listening volume is -20 dB from reference (95 dB peaks for bass), so my thoughts were that I would not notice the loss there, if other aspects of bass quality above 40 Hz were better. While my mix is 70% HT / 30% Music, that doesn't necessarily mean the mix is 70% LFE / 30% mid bass, because a fair amount of bass in movies is music.
That said, most of what is discussed around mid bass vs LFE is around SPL, and if all that I gain is SPL at the mid-bass range and not other "qualities" which can be quantified, then perhaps I won't gain much with pro drivers, and I'm unlikely to notice a difference.
Also 95 dB peaks for bass doesn't account for equal loudness contours, so maybe I need to recalibrate.
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I mentioned I was looking at 11 cuft (300+ liter) with a 16 Hz tune, is there any advantage to going bigger? I'm not planning on pushing SPL either.
I'll be crossing at 80 Hz, I currently have Infinity R162 bookshelves (6.5" woofers with ports, -3 dB @ 67 Hz). They do pretty decent for a lot of music even without a sub, hence my focus on HT usage. Haven't felt the need to upgrade them before, say, trying to get my RT60 down with room treatments first.
Well, simply speaking, twice the Xmax will give you +6db. I don't have much experience with HT sub-bass, but I'll bet 95db at 20 Hz is not going to cut it. Also, if you are not bottoming out the woofer I don't think distortion is going to be an issue, apparently hearing is pretty insensitive to it at very low frequencies.
TBH, with WinISD I think it's best to go through and build your own project file, for driver parameters you can download a file. It's not super complicated. Then it's just juggling box size, port length, etc to find something you are happy with. And realize the sim is not going to be exact, especially with port length. You will want to do impedence sweeps before applying high power.
Or just build a full Marty - or two of them!
To clarify.I'm looking at setups that give 119 dB (UM18-22) vs 116 dB (SAF184.03) at low 20 Hz, according to gsgaudio's performance table for Full Marty's. 95 dB is my guesstimate of what I'll need since I tend to listen at -20 from reference, and the logic is that since I'm listening that quiet, I won't notice the 3 dB difference at 20 Hz.
So my question is if I'll notice any advantages of a pro driver in the mid-bass region (again listening at lower volumes though).
Great point, looks like the CEA-2010 measurement is used for exactly this reason over THD.
Yeah, seems like learning WinISD is inevitable, will definitely try it out.
I am indeed planning to build two full Marty's, I'm just debating which driver to put in them.
I prefer Hornresp.
Here is the input for a 250 liter bass reflex with a port tuning set to around 17 Hz.
With a 500cm2 cross section area port you hit almost 10 m/s from only 100 watts. This is one of the problems with bass reflex. Port velocity should be kept below 10 m/s for low distortion, compression and port turbulence. This is a huge port. 1 meter long.
I would definitely go with a B&C 18TBW100 over the UM18. The UM18 is probably great at low frequency rumble, but will lack a physical and tactile punch.